Heat the oil in a heavy-based frying pan over a medium heat and sauté the onion until golden brown.
Add the ground coriander, ginger and garlic. Sauté for 3-4 minutes until they start to colour and the oil separates. Add the lamb mince and salt, and fry over a high heat for about 5 minutes until it browns and dries up a little. Add the flour.
In a bowl, mix together the coriander, spring onion, mint and green chilli to make a coarse paste. Add the yoghurt to the lamb and sauté for a moment, then add the green herb paste and cook for 4-5 minutes until the oil separates. Add the diced tomatoes, bay leaf and peas. Cook for a further 5-8 minutes until the tomatoes are soft.
Cut the brioche or bread rolls in half and toast until golden brown. Butter while hot.
Serve the mince in little dishes, garnished with fresh coriander leaves, with the buttered brioche or rolls and wedges of lime alongside.